BOGOTÁ, Colombia – Colombia’s President Juan Manuel Santos made plans to fly to a border city Saturday amid soaring tensions with Venezuela that have triggered an exodus of Colombian residents.

In Washington, the U.S. State Department expressed concern about the situation, and urged both countries to resolve the dispute diplomatically.

Santos’ office said the president would visit shelters established in the city of Cucuta for the hundreds of Colombians who have fled Venezuela, carrying with them their meager belongings.

The crisis erupted on Aug. 19 after Venezuela’s President Nicolás Maduro closed the border and then declared a state of emergency following an incident in which three Venezuelan soldiers were shot and wounded by two assailants on a motorcycle.

The two countries have recalled their respective ambassadors and Maduro has said 3,000 troops were being deployed to search “high and low” for Colombian paramilitaries, whom he has blamed for last week’s shooting.

Since then, about 1,000 Colombians have been summarily deported from Venezuela, triggering an exodus of by several thousand more Colombians fearful of being targeted as well.

The U.S. State Department said it was ready to work with other countries “to find a peaceful, humane and enduring solution.”

“As we do so, we urge that special attention be paid to the worsening humanitarian situation along the frontier,” it said.

It stressed the deportations “should take place in accordance with international law, respecting the human rights of all involved, and in coordination with the receiving country.”

“We also believe that refugees with recognized protection concerns should not be deported,” it said.

In a statement late Friday, Santos vowed to continue conducting its foreign relations “with firmness, but with dialogue and diplomacy.”

“We are now concentrating on attending to the humanitarian needs that this situation has generated,” he said.

As the crisis simmered, Maduro announced he was leaving Saturday on a trip to China and Vietnam to drum up financial support for his socialist government.

Venezuela is mired in a deepening economic crisis, made worse by a plunge in oil prices, its main source of hard currency.

Widespread shortages, roaring inflation and rampant crime have undermined support for Maduro, whose ruling party faces legislative elections in December.